The aim of this project is to obtain structural information on polynucleotides and to provide insights into the factors which control structure, principally through X-ray fiber diffraction and model building studies. Current areas include 1) the structure of the poly U-Spermine complex, 2) the structure of a "denatured" polynucleotide, poly A in denaturing solvents, 3) Prediction of structural parameters from observed helical parameters. BIBLIOGRAPHIC REFERENCES: Zimmerman, S. B.: Polynucleotide Models. I. Correlation between Helical Parameters and the Radial Position of the Backbone. Biopolymers 15: 1015-1018, 1976. Zimmerman, S.B.: Polynucleotide Models. II. Prediction of the Radial Position and Tilt of the Bases from the Helical Parameters. Biopolymers 16: 749-763, 1977.